Gelation of liquid hydrocarbons

ABSTRACT

A METHOD FOR GELLING NORMALLY LIQUID HYDROCARBONS, AND THE COMPOSITIONS PRODUCED BY THE METHOD, WHEREIN NORMALLY LIQUID HYDROCARBONS ARE MIXED WITH PRIMARY OR SECONDARY AMINES AND REACTED WITH CARBON DIOXIDE (IN SOME CASES REQUIRING A CATALYTIC AMOUNT OF WATER).

United States Patent Oifice 3,684,733 Patented Aug. 15, 1972 ABSTRACT OF THE DISCLOSURE A method for gelling normally liquid hydrocarbons, and the compositions produced by the method, wherein normally liquid hydrocarbons are mixed with primary or secondary amines and reacted with carbon dioxide (in some cases requiring a catalytic amount of water).

jCROSS REFERENCES TO RELATED APPLICATIONS Applicants incorporate herein the disclosures of copend- 'ing applications of Bannister, Pennace and Smith, entitled Method for Separation and Purification of Aliphatic Amines, Ser. No. 73,633, and of Bannister, Pennace and Curby entitled Device for Thickening, Igniting and Projecting Hydrocarbon Fuels, Ser. No. 73,556, both filed on the same day as the present application.

BACKGROUND OF THE INVENTION hons, such as gasoline, may be ascertained by'reference to the Kirk-Othmer Encyclopedia of Chemical Technology, vol. 4 (1964), pages 893-894 under the section Flame Agents, US. Pat. 2,606,107 of Feiser which issued Aug. 5, 1952, and US. Pat. 2,966,401 of Myerholtz which issued Dec.'27, 1970. The 'Feiser patent is the orig- 'inal Napalm patent and Myerholtz discloses Napalm B which makes use of ABS polymers.

That carbon dioxide reacts with amine and water is known from the Girbotol process as disclosed in Kirk- Othmer supra, vol. 4, page 362. The Girbotol process is used for the recovery of carbon dioxide from burned 'coke and the operation of the process depends upon the reversibile nature of the following reaction:

2HOC2H4NH2 1120 c 0, (HOCglLNHshCO monoethanolamine monoethanolamine carbonate That water is not always a necessary reactant, and that the product of the reaction of an amine and carbon dioxide is in the form of a carbamic acid or its salt is known from the work of F. Goodridge, Trans. Faraday Society 51,

The normally liquid hydrocarbon solvents that are gelled according to the present invention include petroleum hydrocarbons such as naphthas, gasoline, kerosene, fuel oil distillates and the like, pure hydrocarbons such as benzene, toluene, xylene, cyclohexane and the like, and higher boiling hydrocarbon fractions which contain substantial proportions of relatively low boiling hydrocarbons, for example, mixtures of crude oils containing lighter petroleum fractions.

The production of the amines useful in the present invention is disclosed in Kirk-Othmer supra, vol. 2, pages 99-116, under the section Amines (Survey), and pages 116-127 under the section Amines (Lower Aliphatic).

SUMMARY OF THE INVENTION It has been discovered according to the present invention that the addition of small quantities of primary or secondary aliphatic or substituted aliphatic amines to saturated or unsaturated hydrocarbons (in certain cases with varying amounts of water also present for best results) and subsequent treatment with carbon dioxide in the gaseous or solid state results in the formation of solid and/or gelatinous compositions retaining their physical characteristics for long periods of time.

The amines useful in the present invention are aliphatic amines having 1 to 30 carbon atoms, though higher amines may also be useful. The amines are employed generally in the range of 0.1 to 10 percent by weight based upon the amount of liquid hydrocarbon being gelled.

The normaly liquid hydrocarbons having amines therein which are then subjected to a reaction with carbon dioxide have particular utilities as listed below:

(1) As gel compositions for use in devices utilizing thickened fuel, including certain combustion engines; rocket engines; flame throwers, bombs, or other munitions; and similar devices.

(a) Relatively small concentrations of the amines are required. The addition of 1 part of n-butylamine to parts by weight of gasoline, hexane, or similar hydrocarbon produces a rather loose slushy but still adaptable gel of suflicient consistency for use in flame throwers upon the addition of Dry Ice in excess quantity. The addition of 5 parts of the amine to 100 parts of fuel followed by Dry Ice treatment produces a very long lasting rigid gel of quite superior characteristics. In burning tests, the gels are known to retain the original consistency until the fuel has been consumed.

(b) The amines useful in the present invention are commercially available and many are disclosed in'Kirk- Othmer supra (1963), vol. 2, pages 118-119.

(0) The amines are soluble in hydrocarbon fuels and facilitate the thorough and quick mixing of the thickening agents which gives rise to uniform consistencies of the thickened fuel. On the addition of carbon dioxide, gelation occurs over a range of time from almost instantaneous reaction to 5 minutes. It has been observed that the addition of about 1 part of water tol00 parts of amin accelerates the gelation in some cases.

(d) The amines are themselves flammable and in no way detract from the thermal value or flammability of the fuel. The small amount of carbon dioxide incorporated in the gel is inconsequential in terms of the possible effect onlthe flaming characteristics of the fuel.

(e) The gelled compositions are reversible upon the addition of water. Th-us, thickened fuel is easily removed from munitions by the simple expedient of the addition of excess water, e.g. byhosing out. The fuel is unchanged by the overall gelling-degelling process and can be reclaimed for future use. Addition of dilute base (alkali carbonates or hydroxides, for example) or change to the hydrocarbon. Removal of the amine adducts with carbon dioxide can also (be effected by centrifuging the gelled compositions, resulting in degelation.

(2) The hydrocarbon compositions admixed With amines are also useful as fuel thickeners for the prevention of spills, loss of fuel from leaking tanks or holds, and the general overcoming of free surface effects. The characteristics of the compositions, such as case and speed of mixing uniform consistency of the gel, speed of gelation, gel rigidity and reversibility of gelations are useful for long term storage and transport of fuel and in damage control operations. A blanket of carbon dioxide gas provided in a container over the surface of a hydrocarbon fuel containing an amine is advantageous in the prevention of fires in all phases of storage.

(3) Certain amines, and in particular hydrophoblic long chain aliphatic or substituted aliphatic primary and secondary amines, have been shown by the present invention to be quite useful in facilitating collection and removal of oil and other hydrocarbon spills over water surfaces. Thus, addition of less than parts of cetylamine or octadecylamine per 100 parts of oil floating on water, followed by treatment with carbon dioxide, results in formation of waxy curds of a conglomerating nature, which can easily be collected together and subsequently removed, or which can be formed as floating rings effectively isolating hydrocarbon pools contained therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following amines were found to exhibit excellent gelling characteristics when admixed with liquid hydrocarbons and then reacted with carbon dioxide:

Benzyla-mine Benzhydrylamine N-b enzyl-N- Z-cyanoethyl) amine n-Butylamine N-ethyl-N-butylamine N-methyl-N-butylamine N-hexadecylamine N-dodecylamine 1-amino-2-hydroxyhexadecane The following amines were also useful in the gelling of hydrocarbons when reacted with carbon dioxide:

Methylamine n Hexylamine n-Dodecylamine N-methyhN-dodecylamine Morpholine Piperidine Dimethylamine 1-amino-2-propanol 3-amino-1-'propanol n-Propylamine l-propylamine t-Butylamine i-Butylamine Diisobutylamine 1,6-hexanediamine Ethylenediamine 2-methoxyethylamine The concentration of the amines in the hydrocarbons ranges from 0.1 to percent by weight amine based on the hydrocarbon and the preferred range is 1 to 5 percent.

Carbon dioxide is used in the solid, liquid or gaseous states; these reactants are always used in excess in order to insure complete reaction. For each mole of amine used, there must be more than a half mole of carbon dioxide.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent.

4 EXAMPLE 1 A solution of 5 parts of benzylamine is mixed with parts by weight of gasoline in a suitable container. Crushed Dry Ice is added with shaking for a few seconds, whereupon the solution immediately sets up in a gel. Treatment of the gel with water will reverse the gelling process and again make the gasoline available as a liquid when desired.

EXAMPLE 2 Example 1 is repeated in a container with a leak in the bottom. The gasoline leakage quickly slows and then stops.

EXAMPLE 3 A large flat vessel containing several gallons of salt water is layered with motor oil to a depth of /2 inch. A solution of cetylamine in benzene, corresponding to 4 parts of amine to 100 parts of motor oil, is evenly distributed over the oil layer. Another solution of carbon dioxide in benzene, with a calculated excess of carbon dioxide being used in a sufficient amount of benzene to provide a specific gravity less than 1.0, is evenly distributed over the oil layer containing the amine. A slushy gel immediately sets up, of loose consistency but still capable of holding its form to facilitate removal from the surface and/or entrapment of oil pools within enclosed areas. Because of its long chain character this gel tends to be hydrophobic and maintains its gel properties in the presence of water.

EXAMPLE 4 Example 1 is repeated using N-methyl-Nbutylaminc; upon the addition of 0.1 percent by weight of water, a gel of similar consistency is formed.

We claim:

1. A method for gelling a normally liquid hydrocarbon comprising admixing said hydrocarbon with about 0.1 to about 10 percent by Weight of an aliphatic or substituted aliphatic amine having 1 to 30 carbon atoms and reacting the admixture with carbon dioxide in excess quantity.

2. The method of claim 1, wherein said amine concentration is about 1 to about 5 percent.

3. The method of claim 1, further comprising adding traces of water to facilitate gelation.

4. A gelled hydrocarbon consisting essentially of a normally liquid hydrocarbon, and the reaction product of about 0.1 to about 10 percent by weight of an aliphatic or substituted aliphatic amine having 1 to 30 carbon atoms and carbon dioxide in excess of 1 mole per 2 moles of said amine.

5. The gelled hydrocarbon of claim 4, wherein said amine concentration is about 1 to about 5 percent.

6. The gelled hydrocarbon of claim 4, wherein said amine is selected from the group consisting of benzylamine, benzhydrylamine, N benzyl N (2 cyanoethyl) amine, n butylamine, N ethyl N butylamine, hexadecylamine, dodecylamine, and N-methyl-N-butylamine.

References Cited UNITED STATES PATENTS 3,097,168 7/1963 Gibson 44--7 D X 2,958,665 11/1960 Stefcik et al. 2523'l6 RICHARD D. LOVERING, Primary Examiner US. Cl. X.R.

44-7 C, 7 D; 166-294; 2l0--65, DIG. 21; 252-327 

